Telephone-exchange system



Mans, 1923.

//4 van for. RoyD, Conway R. D. CONWAY. TELEPHONE EXCHANGE SYSTEM- FILEDOCT 23.1911;

Patented Mar. 13 i92 UhllTitllO tan arisen ROY D. CONWAY, OF CHATHAM,NEW JERSEY, ASSIGNOB TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEWYORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application filed October 23, 1918.

To all whom it may concern.

Be it known that I, ROY D. CONWAY, a citizen of the United States,residing at Chat-ham, in the county of Morris, State of New Jersey, haveinvented certain new and useful Improvements in Telephone-E); changeSystems, of which the following is a full, clear, concise, and exactdescription.

This invention relates to telephone ex change systems and moreparticularly to telephone circuits incoming to telephone switchboards atwhich are cooperating-circuits for extending such incoming circuits.

The object of this invention is to provide improved signaling means forsystems of this character.

In accordance with a feature of this invention, a trunk circuit incomingto one switchboard and having an electromagnetic switching device forcontrolling a signal associated therewith, is also provided with anelectromagnetic relay which cooperates with the electromagneticswitching device when an extension circuit is connected with the trunkcircuit to control the operation of a signaling device in the extensioncircuit.

In accordance with another feature of this invention, a trunk circuit isprovided with two electro-magnetic relays, one of which controls asignaling device in. a con-- nected extension circuit when a switchingdevice associated therewith is in one position, and when the switchingdevice is in its other position the other relay of the trunk circuitcontrols the extension circuit signal ing device.

In accordance with another feature of this invention a signaling deviceof an exten sion circuit when a switching device thereof is in oneposition, is controlled by a relay of the trunk circuit which operatesover a portion of the talking circuit of the connected extension andtrunk circuits, and when the switching device is in its other positionthe signaling device is then controlled by a relay of the trunk circuitwhich operates over a.

circuit independent of the talking circuit.

For a more complete understanding of this invention, reference should behad to the following description considered in connection with theaccompanying drawing illustrating one embodiment thereof.

As shown in the drawing a trunk circuit A extends from one switchboard,preferably a central office V, to another switchboard Y Serial No.259,426.

which may be of theprivate branch exchange type. At the central otficeswitchboard there is provided a link circuit B which may be employed ininitiating a call over the trunk circuit A or in answering a callincoming thereover. At the private branch exchange switchboard Y thereis provided an extension circuit C, which is preferably employed inholding the trunk circuit while the operator thereat is locating a partyfor whom acall incoming over the trunk circuit from the central oflicehas been received or when expectinga call over the trunk circuit. Theapparatus shown to the left of the dotted line 2-2 is located at thecentral office switchboard and that shown to the right thereof islocated at the private branch ex change switchboard. At the privatebranch exchange switchboard theremay be provided link circuits similarto link circuit B which may be employed to establish connections betweenthe trunk circuit and telephone lines (not shown) which terminate at theprivate branch exchange switchboard. It will also vbe understood thattelephone lines terminate at the central otlice switchboard, but sincethese form no part of the present invention they are .not shown.

The nature of the present invention is such that it is believed that itwill be thoroughly understood from a description of the operation of thesystem shown in the drawing and it will be so described.

The operator at the switchboard X desiring to extend a call to theprivate branch exchange switchboard Y may insert plug 5 of cord circuitB into ack 6 of trunk circuit A, thereby lighting lamp 7 and operatingcut-off relay 8. This operator may thereupon actuate ringing key 9,causing the energization of ring-up relay 10 over a circuit from thesource or ringing current 11, lower alternate contact of ringing key 9,ring contacts of the plug 5 and the jack 6, resistance 1.2, condenser13. contact 14 of slow-to-opcrate relay 15, left-hand winding of relay10,

. tip contacts of ack 6 and plug 5 and the upper alternate contact ofringing key 9 to ground. Relay 10 upon being energized completes alocking circuit for itself from battery through contact 20 of relay andthe contact and right-hand winding of relay 10 to ground. At the sametime lamp 21 is lighted over a circuit from battery through contact ofrelay 15, contacts of relay 10,

contact 22 of relay 23 and lamp 21 to ground. The lighting of lamp 21serves as a line signal to the P. B. X. operator. The energization ofrelay 10 also causes the operation of busy signals 16 and 17 associatedwith the trunk jacks at the P. B. X. These signals operate ,over acircuit from battery through contact 20 of relay 15, contacts of relay10, contact 18 of relay 23, contact 41 of relay 15, windings of signals17 and 16 and resistance 53 to ground.

The P. B. X. operator observing the lighted condition of the lamp 21 mayinsert the plug of a cord similar to cord circuit B into jack 24 of thetrunk circuit. Belay 25 of the trunk circuit A thereupon operates,causing the energization of relay 26 over a circuit from battery throughthe winding of sloW-to-operate relay 15, left-handwinding of relay 26and right-hand contact of relay 25'to ground. Relay 23 does not operateat this time due to the high impedance of the winding of the repeatingcoil and the left-hand winding of relay 23. Before the winding of relay23 becomes sufli'ciently saturated to cause the relay to operate itscircuit is interrupted by the relay 15, the o eration of which will belater described.

pon the operation of relay 25 supervisory relay 27 of cord circuit B andrelay 28 of the trunk circuit are energized over a circuit from batterythrough the winding of supervisory relay 27, lower normal contact ofringing key 9, ring contacts of the plug 5 and the jack 6, contact 29 ofrelay 23, left hand contact of relay 25, contact 35 of relay 15, windingof relay 28, tip contacts of the jack 6 and the plug 5 and upper normalcontact of the ringing key 9 to ground. Upon the energization ofsupervisory relay 27 a shunt circuit including resistance 36 isestablished about the supervisory lamp 7, causing the extinguishmentthereof. The energization of relay 28 causes the closure of its contact,which establishes a short circuit about the left-hand winding of therelay 26. The lamp of the cord circuit connected with the jack 24 doesnot light until. the low resistance right-hand winding of relay 26 isincluded in parallel with the high resistance left-hand winding of relay25, thereby reducing the resistance of the lamp circuit. Slow-to-operaterelay 15 operates in series with relay 26 upon the closure of theright-hand contact of relay 25. This relay 15 is made slow to operate,so that impedance coil 39 will not be included in series with relays 27and 28 until after these two relays have operated; Relay 15 inoperating, opens contact 20, releasing relay 10 and extinguishing thelamp 21, closes contact 40 and opens contact 41, maintaining v the busysignals 16 and 17 operated, opens contact 35, removing the short circuitfrom the impedance coil 39 which it thereby-in sistance 12, and aportion of the ring talking strand of the trunk circuit A back to thecontact 29 of relay 23. The P. B. X.

operator ma actuate the listening key of the connectec cord circuitimmediately after plugging in, and the central oilice operator mayactuate listening key 19 when the supervisory lamp 7 is extinguished.The operators may now converse, the central oflice operator advising theP. B. X. operator of the number of the line called or the name of theparty wanted.

It the call is for a party whom the P. B. X. operator must locate, thecord circuit will be disconnected from the trunk circuit,

causing the release of the various operated relays, and plug-37 of theholding cord or extension circuit C inserted into the jack 24 for thepurpose of holding the trunk circuit until the party is located. Theholding key 38 of this holding cord circuit may be actuated before orafter the insertion of the plug 37 into the jack 24. If this key is notactuated when plugging in, relay 23 will operate over a circuit frombattery through contact 20 of relay 15, left-hand winding of relay, tipcontacts of the jack 24 and the plug 37 and the upper normal contacts oflistening key 49 and holding key 38 to ground. No other apparatus willfunction until the holding key is actuated, and when this key isactuated relay 23 will release. If this key 38 is actuated before theconnection of the cord circuit with the trunk circuit, relay 23 will notoperate upon plugging in, but immediately upon insertion of the plug inthe jack, relay 25 of the trunk circuit will be operated over a circuitfrom battery through high resistance 30 the lower alternate contact ofthe holding key 38, sleeve contacts of the plug 37 and. the jack 24 andboth windings of relay 25 to ground. Relays 26, 28 27 and 15 will nowoperate in sequence and in the manner previously described in connectionwith the functioning of these relays when the other cord circuit wasconnected with the trunk circuit. W hile reeaaae energized when includedin series with the high resistance coil 30 and when its left-- handwinding is short-circuited. Upon the insertion of the plug 37 in thejack 24 and when the holding key 38 is actuated, slow-tooperate relay 45is energized and in turn causes the energization of the slow-to-operaterelay 46. The operation of relay 46 includes low resistance coil 47 andlamp 48 in parallel with the high resistance coil 30. These relays 45and 46 are purposely made slow in operating in order that the lamp 48may not be included in parallel relation with the high resistance coil30 until after the operation of relay 28 and the release of relay 26.Otherwise relay 26 would remain energized and cause the lighting of thelamp 48 which is undesirable at this time. WVith the holding cordconnected with the trunk circuit and the holding key actuated,supervisory lamp 7 of the cord circuit B, lamp 21 of the trunk circuit Aand lamp 48 of the holding cord circuit C are extinguished.

If the central ofiice operator should desire to signal the P. B. X.operator, while the cord circuits B and C are connected with the trunkcircuit A and the holding key 38 is actuated this may be done bywithdrawing the plug 5 from the jack 6 and reinserting it therein ormerely by momentarily actuating the ringing key 9. The withdrawal of theplug or the actuation of the ringing key causes the release of relay 28.thereby removing the short circuit ofthe left-hand winding of relay 26which is now included in series with the winding of relay 15. Relay 26is thereupon energized, closing its contact, thereby connecting the lowresistance right-hand winding of relay 26 in parallel with the highresistance left-hand winding of relay 25. The resistance of the sleevecircuit is thereby reduced to such an extent that the lamp 48 of theholding cord circuit C is lighted over a circuit from battery throughlow resistance coil 47, left-hand alternate contact of relay 46, lamp48, right hand alternate contact of relay 46, lower alternate contact ofholding key 38, sleeve contacts of the plug 37 and jack 24. righthandwinding of relay 25, and the left-hand winding of relay 25 and theright-hand winding of relay26 in parallel to ground. The lighting ofthis lamp 48 serves as a signal to the P. B. X. operator. Thereinsertion of the plug 5 into the jack 6 or the restoration of theringing key 9 to normal position causes the: energization of supervisoryrelav 27 and relay 28. The reestablishment of the short circuit of thelefthand winding of the relay 26 by the closure of the contact of relay28 does not cause the release of this relay 26 for the reason that thelow resistance coil 47 and the lamp 48 are now in parallel relation withthe high resistance coil. 30. whereby the righthand winding of relay 26receives sufiicient current to maintain this relay energized.

The P. B. X. operator may respond to the signal manifested by thelighting of the lamp 48 by restoring the holding key 38 to normalposition and actuating the listening key 49 to connect the operatorstelephone set with the trunk circuit. The restoration of the holding key38 to normal position causes the release of relays 45 and 46, therebyextinguishing the lamp 48. The restoration of this key 38 to normalposition also causes the release of relay 26 and the momentary releaseof relays 25, 28 and 27, but these are immediately reenergized upon theactuation of the listening key 49 through the closure of the middlealternate contact thereof.

Should the P. B. X. operator desire to hold the trunk circuit A so thatan outgoing call thereover may be made at some later time, but not totie up the trunk circuit so that incoming calls may not be receivedthereover, the plug 37 may be inserted into the jack 24 with the holdingand listening keys 38 and 49 in normal. position. Upon the insertion ofthe plug 37 into the jack 24 relay 23 of the trunk circuit operates overthe hereinbefore-traced circuit. The operation of relay 23 causes theoperation of the busy signals 16 and 17 over a circuit from batterythrough contact 52 of relay 23, contact 41 of relay 15, the windings ofbusy signals 17 and 16 and resistance 53 to ground. If the centraloffice operator should now insert the plug 5 into the jack 6 and actuatethe ringing key 9, relay 10 would be energized and locked up in themanner hereinbefore described, but the lamp 21 would not be lighted. Thelamp 48 of the holding cord circuit, however, would be lighted over acircuit from battery through contact 20 of relay 15, contacts of relay10. contact 50 of relay 23, resistance 51, ring contacts of the jack 24and the plug 37, lower normal contact of listening key 49, left-handnormal contact of relay 46, lamp 48 and the righthand normal. contact ofrelay 46 to ground. The lamp 48 now serves as a line signal to the P. B.operator. Observing the lighted condition.v of the lamp 48, the P. B. X.operator may actuate listening key 49 to connect the telephone set withthe trunk circunt. The actuation of this key 49 causes. the release ofrelay 23 and the operationv of relays: 25.26. 28. 27 and 15 followed bythe release of relays 26 and 10. The energizing circuit for relay 25 nowincludes the middle alternate contact of the listening key 49 instead ofthe lower contact of the holding key 38. The lamp 48 is alsoextinguished.

If. while both the central office cord circuit B and the P. B. X. cordcircuit C are connected with the trunk circuit A, the P. R. X. operatordesires to signal the.

tral ofliceoperator, this may be done by in-- termittently actuating key55. lfhe intermittent actuation of this key causes the intermittentenergization of relay-23 which intermittently opens and closes thebridge across the talking conductors of the trunk circuit. Supervisoryrelay 27 is deenergized upon each opening of the bridge whereby thesupervisory lamp 7 is intermittently lighted during the intermittentactuation of the key 55.

What is claimed is:

1. A telephone exchange system comprising a trunk circuit, a relayconnected with the trunk circuit, a signaling device therein, a relaycooperating with the trunk relay to control the operation of the trunkcircuit signaling device, a link circuit, and a direct current signalingdevice therein operated over a circuit including a contact of the secondrelay when the link circuit is subsequently connected with thetrunkcircuit.

2. A telephone exchange system comprising a trunk circuit, a relayconnected there with, a signaling device in the trunk circuit, asecondrelay, an operating circuit for the signaling device completedthrough a contact of the second relay upon the energization of the firstrelay, a link circuit subsequently connected with the trunk circuitcausing the operation of the second relay, and a direct currentsignaling device in the link circuit operating over a circuit controlledby the energized relays.

3. A telephone exchange system comprising a trunk circuit, a relayresponsive to ringing current connected therewith, a signaling device inthe trunk circuit, an operating circuit for said signaling devicecompleted through a contact of said relay, a link circuit, a signalingdevice therein, and a normally deenergized relay cooperating with thefirst relay when the first relay is energized to cause the operation ofthe trunk circuit signaling device and when energized by the connectionof the link circuit with the trunk circuit cooperating with theenergized first relay to cause the operation of the link circuitsignalingdevice.

4. A telephone exchange system comprising a trunk circuit, a relaytherein responsive to ringing current, another relay in the trunkcircuit responslve to dlrect current, a link circult connected with thetrunk circuit, a two-position switching device in the link circuit and asignaling device in the link circuit controlled by the first mentionedrelay when the switching device is in one position and by the secondmentioned relay when the switching device is in its other position.

5. A telephone exchange system comprising a trunk circuit, a relay inthe trunk cir cuit responsive to ringing current, anotherrelay in thetrunk circuit responsive to direct current, a link circuit connectedwith the trunk circuit, a two-position switching device in the linkcircuit, a signaling device in the link circuit, a third relay in thetrunk circuit cooperating with the ringing response relay when theswitching device is in one position for controlling-the signalingdevice, and a fourth relay in the trunk circuit cooperating with-thedirect current response relay whenthe switching device is in its otherposition to control the signal: ing device.

6. In a telephone exchange system, in combination, a trunk circuitcomprising talking conductors, a ringing response relay normallyconnected with the talking conductors, a direct current response relaynormally disconnected from the talking conductors, a link circuitconnected with the trunk circuit, a two-position switching device in thelink circuit, a signaling device in the link circuit controlled by theringing response relay when the switching device is in one position, andmeans in the trunk circuit effective when the switching device is movedinto its other position to'disconnect the ringing response relay fromthe talking conductors and to connect the direct current response relaythereto whereby the direct current response relay cooperates with saidmeans for controlling said signaling device.

7 In a telephone exchange system, in combination, a trunk circuitcomprising a pair of talking conductors, a relay for the trunk circuitconnected with the talking conductors and responsive to ringing current,another relay in the trunk circuit normally disconnected from thetalking conductors'and responsive to direct current, a link circuit, atwo-position switching device in the link circuit, a third relay in thetrunk circuit energized upon the connection of the link circuit with thetrunk circuit when the switching device is in one position, a signalingdevice in the link circuit, an operating circuit for the signalingdevice includinga portion of one of the talking conductors and contactsof the third relay when the ringing response relay is energized, afourth relay in the trunk circuit energized when the switching device ismoved into its other position and cooperating with the third relay toconnect the direct current response relay with the talking conductors,and an operating circuit for the signaling device controlled by thefourth relay and including a contact of the switching device when in itssaid other position.

8. A telephone exchange system comprising an incoming circuit, anextension circuit connected therewith, a two-positioned neoted incomingand "extension circuits when the switching device is in one position tocontrol the signaling device, and a second relay in the incoming circuitoperating independentl of the first relay to control the signalingdevice when the switching device is in its other position.

9. In a telephone exchange system, a first exchange, a second exchange,a trunk circuit extending between said exchanges, means at said firstexchange for signaling over said trunk circuit, asignaling deviceassociated with said trunk circuit at said second exchange, a relay atsaid second exchange responsive to said signaling means when a call isinitiated over said trunk circuit to actuate said trunk circuitsignaling device, an operators link circuit at said second exchange, asignaling device therefor, and a second relay at said second exchangecontrolled from said second exchange and cooperating with said firstmentioned relay when said link circuit is connected to said trunkcircuit to actuate said signaling device of said operators link circuit.

10. In a telephone exchange system comprising an incoming circuit, alink circuit associated therewith, a signaling device associated withsaid incoming circuit, a signaling device associated with said linkcircuit, energizing circuits. for each of said devices, a relay in saidincoming circuit, a second relay associated therewith, said relayserving to open the operating circuit of the signaling device in saidincoming circuit and to close the operating circuit of the signalingdevice in said link circuit while said first relay is energized.

11. In a telephone exchange system, a first exchange, a source ofcurrent thereat, a trunk circuit, a source of current associatedtherewith, a second exchange and a source of current thereat, asignaling device in said second exchange, a relay in said trunk circuitat said second exchange, said relay being provided with a low resistanceand a high resistance winding, a second relay associated with the firstrelay, said relay being responsive to current from the source of thetrunk circuit and current from the source at said second exchange andservin when energized to short circuit the higli resistance winding ofthe first relay, and

means responsive to current from the source at said first exchangecooperating with said relays to control the signal device associatedwith said second exchange.

12. A telephone exchange system comprising an exchange, a source ofcurrent, a trunk circuit, a relay connected with said circuit, asignaling device in said trunk circuit, a link circuit, a source ofcurrent in said link circuit, a relay cooperating with the first relayto control said signaling device, a double wound relay in said trunkcircuit, energized by the said source of current associated with saidlink circuit, a second double wound relay, a source of current in saidtrunk circuit for energizing one of the windings of said relay andthereby shunting one of the windings of said first mentioned doublewound relay by the other winding of said second mentioned double woundrelay to control the operation of the signaling device in said linkcircuit, and means responsive to current from the first mentioned sourcefor also controlling the second double wound relay.

13. In a telephone exchange system, a first exchange having a source ofcurrent therein, a trunk circuit, a source of current and a signalingdevice in said trunk circuit, a second exchange, a signaling device, asource of current and a two position switching device in said secondexchange, a relay in said trunk circuit energized by current from thesource at the first exchange, a second relay in the trunk circuitenergized by current from the source in the trunk circuit andcooperating with the first relay to control the signaling device in thetrunk circuit and to control the signaling device in said secondexchange when the switching device is in one position, a third relayenergized by current from the source in the second exchange and a fourthrelay responsive to current from the sources in said trunk circuit andin the second exchange and cooperating with the third relay to controlthe operation of the signaling device in the second exchange when theswitching device is in its other position.

In Witness whereof, I hereunto subscribe my name this 18th day ofOctober, A. D.

ROY D. CONWAY.

